An on-hook EOH indicating telephone includes a parallel set detector, an EOH signal detector, and an indication module to activate a configurable audible and/or visual alert indicating that another telephone is off-hook and should be hung up. The audible alert may be a unique ringing of the otherwise conventional ringer (e.g., every 5 minutes, at a unique cadence or frequency, etc.), or may be an audible tone output from the speaker of the on-hook EOH indicating telephone. The visible alert may be, e.g., a text message on a display of the on-hook EOH indicating telephone, a blinking, flashing, etc. of an LED, or other visible attention getting technique. When the central office presents the extended off-hook (EOH) notification signal to the desired telephone line, the invention-equipped telephone detects a parallel set in use, and then listens for the EOH signal. Upon receiving the EOH signal, the inventionequipped telephone will uniquely ring, visibly illuminate, flash, or otherwise alert the users in the household that another telephone is off-hook. This audible and/or visible alert at the on-hook EOH indicating telephone is over and above that audibly output by the parallel telephone which caused the receipt of the EOH signal.